Effects of Roasting Temperature and Time on Physicochemical, Sensory, Caffeine, Antioxidant, and Chemical Profiles of Robusta Coffee (Coffea Canephora)

Roasting temperature and time strongly influence the physicochemical, sensory, and chemical characteristics of Robusta coffee, but these responses should be interpreted simultaneously rather than using a single quality parameter. This study evaluated the effects of roasting temperature (190, 200, 210, 220, and 230°C) and roasting time (10, 14, and 18 min) on moisture, ash, pH, antioxidant activity, sensory acceptance, caffeine content, and chemical compound profile of Robusta coffee (Coffea canephora). A 5 × 3 factorial Completely Randomized Design was applied, with two replications for each of the 15 treatment combinations. Sensory acceptance was evaluated by 25 untrained consumers using a five-point hedonic scale. Moisture content ranged from 0.550 to 1.866%, while ash content ranged from 4.525 to 4.959%. Roasting time significantly affected pH (p = 0.002), whereas temperature and the temperature × time interaction did not. Temperature, time, and their interaction did not significantly affect DPPH IC50 (p > 0.05), although the lowest numerical IC50 was 71.68 ppm at 210°C for 18 min. Sensory acceptance was highest at 18 min, with the highest mean scores for colour, aroma, and flavour of 3.67, 3.37, and 3.12, respectively. Caffeine content in the three sensory-selected treatments ranged from 0.5582 to 0.8156% as-is. GC-MS identified six compounds, with caffeine having the largest relative peak area (90.91%; SI 97). Overall, 220°C for 18 min showed the strongest sensory response within the tested treatments; however, it should not be interpreted as an overall optimum without a multi-response optimization procedure Contribution to Sustainable Development Goals (SDGs):SDG 9: Industry, Innovation and InfrastructureSDG 12: Responsible Consumption and Production